Eddy current braking apparatus



Oct. 18, 1960 P. E. BESSIERE EDDY cumm- BRAKING APPARATUS Filed June 9.1958 m T m v w W hm m QN H I a Mn MN. U N M Q 3 @R H 9. I m o l NQ w a w5 N w I ATTORNEY United States Patent EDDY CURRENT BRAKING APPARATUSPierre Etienne Bessiere, Neuilly-sur-Seine, France, as-

signor to Compagnie Telma, Paris, France, a society of France Thepresent invention relates to eddy current braking apparatus, inparticular for use on road or railway vehicles, on hoisting devices,mining apparatus, and so on.

The apparatus according to the present invention is of the typeincluding a rotor acting as armature and constituted by two parallelannular discs located at a distance from each other and carried by theshaft to be braked and a stator acting as inductor, disposed in thespace between said two discs and including a support on which aremounted on the one hand a central sleeve in which said shaft isjournalled and on the other hand the cores of the inductorelectromagnets, said cores projecting on either side of said support,between it and said armature discs.

The object of this invention is to provide an apparatus of this kindwhich is better adapted to meet the requirements of practice than thoseused for the same purposes up to this time, in particular from the pointof view of its mounting and its upkeep.

For this purpose, according to the present invention, the central sleeveis provided at its periphery with a flange and said support is providedwith a central aperture slipped on said sleeve and applied in aremovable manner against one face of said flange.

Other features of the invention will become apparent in the course ofthe following detailed description of some specific embodiments thereofwith reference to the accompanying drawings, given merely by Way ofexample and in which:

Fig. 1 shows an embodiment of my invention in sectional view on the lineII of Fig. 2.

Fig. 2 is an end View of this apparatus with parts cut away.

Fig. 3 shows, on an enlarged scale, a detail of the apparatus of Fig. l.

The apparatus includes:

(a) A rotor acting as the armature of said apparatus and including twoparallel annular discs 2 and 2a located at a distance from each otherand carried by hubs 53 and 53a fixed to shaft 1; and

(b) A stator acting as the inductor, disposed between these discs 2, 2aand including a support, constituted by two opposed cup-shaped elements37 and 37a the flat portions of which are applied against each other, aplurality of electro-magnets the cores 4 of which extend through saidflat portions to which they are welded, at right angles thereto, and acentral sleeve 5b carried by support 37, 37a and in which shaft 1 isjournalled.

According to my invention, support 3737a is det-achably assembled withcentral sleeve 5b.

For this purpose, sleeve 5b carries, preferably integral therewith, aflange 39a projecting outwardly from the periphery thereof. Support37-37a is provided with a central aperture 3838a adapted to fit aroundsleeve 5b against one face of flange 39a. Easily removable means, suchas screw-bolts 79 provided at places along the edge of aperture 3838a,are provided for securing said edge to face of flange 39a.

2,957,093 Patented Oct. 18, 1960 Preferably, sleeve 5b is made bymolding of malleable cast iron and each of the support cup-shapedelements is obtained by stamping of a steel sheet. Said elements 37 and37a are provided with respective radial grooves located opposite eachother so as to form a housing adapted to accommodate a lubrication tube65, and also to stiffen support 3737a.

At the places where screw-bolts 79 pass therethrough, members 37 and37a, which are spaced apart, are held at the desired distance from eachother by thick washers 80 which may be secured, for instance by welding,to one of the parts 37 and 37a.

Tube 65 opens into the central hole of one of said washers 80. The outerdiameter of the corresponding screw-bolt 79 is substantially smallerthan the diameter of the central hole of said washer 80 and of a coaxialcylindrical housing formed in flange 39a. Flange 39a is further providedwith a radial conduit 67a extending between said cylindrical housing andthe inner wall of sleeve 51). Thus, grease supplied by a lubricator 66can be fed through tube 65, the space around screw 79 and conduit 67a tothe inside of sleeve 5b.

According to another feature of the present invention, shaft 1 isjournalled in two roller bearings mounted in the ends of sleeve 5b. Theinner races 81 and 81a of said rollers constitute conical rollingsurfaces the generatrices of which converge toward the axis of shaft 1in the direction going from the outside of sleeve 5b toward the insidethereof. Thus, the centers of thrust O and 0a of these hearings are at agreater distance from each other than the middle plane of the bearings,as shown by Fig. 1.

As stability increases with the distance between centers 0 and 0a, thearrangement above described is very advantageous, especially in view ofthe fact that the distance between the bearings is necessarily smallerthan that between the hubs 53 and 53a of the rotor discs 2 and 2a.

Advantageously, between the outer race of each of the above mentionedbearings and the central sleeve 5b, there is inserted a mounting ring82, 82a provided at its inner edge with an inward flange 83, 83a againstwhich is applied the inner edge of the outer race of the correspondingroller bearing, the outer edge of mounting ring 82, 82a being providedwith an outward flange 84, 84a adapted to fit against the correspondingedge of central sleeve 5b.

Screw-bolts 85, 85a passing through flanges 84, 84a and screwed incentral sleeve 5b keep rings 82, 82a in position with respect to saidsleeve. These rings 82 and 82a have the advantage that they can easilybe replaced in case of wear and tear.

In order to permit of adjusting the play in the roller bearings, thereis provided, at least at one of the ends of sleeve 5b, a screw-threadedadjustment ring 86 screwed in the periphery of sleeve 5b and bearingagainst flange 84. When this adjustment ring 86 is screwed more or less,ring 82 is positioned as desired with respect to sleeve 5b, whichpermits of adjusting the play in the roller bearings.

Means are provided for fixing said adjustment ring in the desiredposition. For this purpose, a sheet metal element 88 of cylindricalshape surrounding flange 84 is pro vided on one of its edges with radialprojections 87 provided with holes 88a through which screw-bolts 85pass. The other edge of cylindrical piece 88 is provided with teeth 89bent at right angles to part 88, so as to be located in a planeperpendicular to the axis of shaft 1 along one end face of ring 86. Ring86 is provided at its periphery located opposite teeth 89 with at leastone notch 90 adapted to accommodate one of these teeth which has beenbent obliquely for this purpose.

In order to adjust the play in the roller bearings, screwbolts 85 areloosened and ring 86 is unscrewed with respect to sleeve 517 until theplay has the desired value. Then, bolts 85 are screwed'tight and thetooth 89 located opposite notch 90 is bent so as to be engaged into saidnotch, as shown by the drawings.

Bolts 88' may be prevented from unscrewing, as shown by Fig, 2, bybending against one of the sides thereof a portion of the projection 87through which they pass.

In order further to increase the accuracy of adjustment, the holes 88aprovided in projections 87 may be made in the form of circular arcs,whereby, for any angular position of ring 86, it is possible to bringone of the teeth 89 opposite notch 90.

In a general manner, while I have, in the above description, disclosedwhat I deem to be practical and efficient embodiments of my invention,it should be well understood that I do not wish to be limited thereto asthere might be changes made in the arrangement, disposition and form ofthe parts without departing from the principle of the present inventionas comprehended within the scope of the accompanying claims.

What I claim is:

1. For use to slow down the movement of rotation of a shaft, an eddycurrent braking apparatus which comprises, in combination, a rotorincluding said shaft and two metal discs parallel to each other fixed onsaid shaft coaxially therewith and at a distance from each other, and astator including a sleeve coaxially surrounding a portion of said shaftlocated between said rotor discs, bearings for said shaft mounted insaid sleeve, a flange carried by the outer periphery of said sleeveextending transversely to said shaft, said flange being located to oneside of a plane transverse to the shaft axis and equidistant from thebearings, a support having a central aperture slipped on said sleeve,the face of said support around the edge of said aperture being appliedagainst one face of said flange, means for detachably securing saidsupport to said flange, a plurality of electro-magnet cores of elongatedshape having each its longer dimension parallel to the axis of saidshaft, said cores being fixed directly on said support and regularlydistributed about said axis, each of said cores extending throughoutsaid support and on opposite sides thereof to short distances from theinner faces of said rotor discs respectively, and a plurality ofelectro-magnet windings surrounding said cores.

2. For use to slow down the movement of rotation of a shaft, an eddycurrent braking apparatus which comprises,in combination, a rotorincluding said shaft and two metal discs parallel to each other fixed onsaid shaft coaxially therewith and at a distance from each other, and astator including a sleeve coaxially surrounding a portion of said shaftlocated between said rotor discs bearings for said shaft mounted in saidsleeve, a flange integral with said sleeve projecting outwardlytherefrom transversely to said shaft, said flange being located to oneside of a plane transverse to the shaft axis and equidistant from thebearings, a support constituted by two cupshaped metal elements havingflat portions applied against each other along a common planeperpendicular to said shaft and located between said discs, therespective outer peripheral portions of said elements extending awayfrom each other on either side of said plane, said elements beingprovided with registering respective central circular apertures, saidcentral apertures fitting on the outer wall of said sleeve, both on thesame side of said flange, the face of said support around the edge ofone of said apertures being applied against one face of said flange, theedges of said central apertures being spaced apart from each other, atleast at some places, annular Washers interposed between said edges atsaid places, screw bolts extending through said edges, the central holesof said washers and said flange for detachably securing said supportelements to said flange, a plurality of electro-magnet cores ofelongated shape having each its longer dimensions parallel to the axisof said shaft, said cores being fixed directly on said support andregularly distributed about said axis, each of said cores extendingthroughout said flat portions of said support elements and on oppositesides thereof to short distances from the inner faces of said rotordiscs respectively, and a plurality of electromagnet windingssurrounding said cores.

3. An apparatus according to claim 2 in which said two flat portions areprovided with respective radial grooves facing each other and passingthrough the center of one of said washers, further including alubrication tube housed in said grooves and extending from the outerperiphery of said support elements to the central hole of said washer,said central hole being of a diameter greater than the outer diameter ofthat of said screw bolts which extends through said washer, said sleevebeing provided with a conduit starting from the central hole of saidwasher and opening into the inner wall of said sleeve, wherebylubricating grease can be fed into said sleeve.

4. For use to slow down the movement of rotation of a shaft, an eddycurrent braking apparatus which comprises, in combination, a rotorincluding said shaft and two metal discs parallel to each other fixed onsaid shaft coaxially therewith and at a distance from each other, astator including a support having a portion thereof located between saidrotor discs, a plurality of electro-magnet cores of elongated shapehaving each its longer di mensions parallel to the axis of said shaft,said cores being fixed on said support and regularly distributed aboutsaid axis, each of said cores extending from said support to shortdistances from the inner faces of said rotor discs respectively, aplurality of electro-magnet windings surrounding said cores, and asleeve carried by said support and coaxially surrounding a portion ofsaid shaft located between said rotor discs, and thrust roller bearingsfor said shaft mounted in said sleeve at the respective ends thereof,each of said thrust bearings including an outer race mounted in one endof said sleeve, an inner race mounted on said shaft and rollersinterposed between said races, the rollers of each of said rollerbearings having their axes located along the generatrices of a conecoaxial with said shaft, said cones flaring in opposed directionsrespectively so that the centers of thrust of said bearings, located onthe axis of said shaft, are at'a distance from each other greater thanthe distance between the respective middle planes of said bearings. v

5. For use to slow down the movement of rotation of a shaft, an eddycurrent braking apparatus which c0mprises, in combination, a rotorincluding said shaft and two metal discs parallel to each other fixed onsaid shaft coaxially therewith and at a distance from each other, astator including a support having a portion thereof located between saidrotor discs, a plurality of electro-magnet cores of elongated shapehaving each its longer dimensions parallel to the axis of said shaft,said cores being fixed on said support and regularly distributed aboutsaid axis, each of said cores extending from said support to shortdistances from the inner faces of said rotor discs respectively, aplurality of electro-magnet windings surrounding said cores, a sleevecarried by said support and coaxially surrounding a portion of saidshaft located between said rotor discs, and two mounting rings eachfitted in one of the ends of said sleeve, each of said rings including,at one edge thereof, an outward flange applied against the correspondingedge of said sleeve and, at the other edge thereof, an inward flangelocated inside said sleeve, and thrust roller bearings for said shaftmounted in said sleeve at the respective ends thereof, each of saidthrust bearings including an outer race fitted in one of said ringsrespectively against the inward flange thereof, an inner race mounted onsaid shaft and rollers interposed between said races, the rollers ofeach of said roller bearings having their axes located along thegeneratrices of a cone coaxial with said shaft, said cones flaring inopposed directions respectively so that the centers of thrust of saidbearings, located on the axis of said shaft, are at a distance from eachother greater than the distance between the respective middle planes ofsaid bearings.

6. An apparatus according to claim 5 further comprising an adjustmentring coaxial with said sleeve and screwed on one end thereof, saidadjustment ring being 10 2,833,945

in contact with the outward flange of the corresponding mounting ringwhereby the position of said last mentioned mounting ring axially withrespect to said sleeve can be adjusted by screwing more or less saidadjustment ring on said sleeve.

7. An apparatus according to claim 6 further including means operativelyassociated with said sleeve and engageable with said ring for lockingsaid adjustment ring in desired position with respect to said sleeve.

References Cited in the file of this patent UNITED STATES PATENTS2,632,859 Bessiere Mar. 24, 1953 Bessiere May 16, 1958 FOREIGN PATENTS495,878 Belgium Sept. 16, 1950

